On Fri, 10 Aug 2012 10:51:19 +0800 Shaohua Li <shli@xxxxxxxxxxxx> wrote:
> @@ -4094,6 +4159,19 @@ static void make_request(struct mddev *m
> bi->bi_next = NULL;
> bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
>
> + /* block layer doesn't correctly do alignment even we set correct alignment */
> + if (unlikely(bi->bi_rw & REQ_DISCARD)) {
> + int stripe_sectors = conf->chunk_sectors *
> + (conf->raid_disks - conf->max_degraded);
This isn't right when an array is being reshaped.
I suspect that during a reshape we should only attempt DISCARD on the part of
the array which has already been reshaped. On the other section we can
either fail the discard (is that a good idea?) or write zeros.
> +
> + logical_sector = (logical_sector + stripe_sectors - 1);
> + sector_div(logical_sector, stripe_sectors);
This would look better with DIV_ROUND_UP_SECTOR_T().
> + sector_div(last_sector, stripe_sectors);
> +
> + logical_sector *= stripe_sectors;
> + last_sector *= stripe_sectors;
> + }
> +
> for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
> DEFINE_WAIT(w);
> int previous;
> @@ -4114,6 +4192,11 @@ static void make_request(struct mddev *m
> if (mddev->reshape_backwards
> ? logical_sector < conf->reshape_progress
> : logical_sector >= conf->reshape_progress) {
> + /* The stripe will be reshaped soon, ignore it */
> + if (bi->bi_rw & REQ_DISCARD) {
> + spin_unlock_irq(&conf->device_lock);
> + goto next_stripe;
> + }
> previous = 1;
> } else {
> if (mddev->reshape_backwards
> @@ -4202,6 +4285,12 @@ static void make_request(struct mddev *m
> finish_wait(&conf->wait_for_overlap, &w);
> break;
> }
> +next_stripe:
> + /* For discard, we always discard one stripe */
> + if (unlikely((bi->bi_rw & REQ_DISCARD) &&
> + !((logical_sector + STRIPE_SECTORS) % conf->chunk_sectors)))
You are using '%' on a sector_t value. That isn't right - need to use
sector_div().
Thanks,
NeilBrown
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